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gbrown

Geoff on Bkool
Location
South Somerset
I'd love to be 70kg virtually and in real life. :biggrin:

Looking at recording the really fast guys blasted off the line at over 400 watts and kept it going for quite a while. I don't think I could push that hard, so early, without paying with burning my whole matchbox let alone one match.

The fast starters are exploiting a weakness in the bkool simulation and the way that the trainers apply resistance.

When the trainer is not spinning it has no resistance (as the resistance depends on the metal disc moving under the magnets) and so if you hit it really hard from no/low rpm you can get a huge spike in speed before the resistance catches up.

I checked the max speeds for a few riders, and found the fast starters were hitting crazy speeds in the first 500 meters, particularly Bridgy, Bill and Rick!

BillS = 94.4 kph
LBHIFI = 70.8
Bridgy = 114.1
RickB = 86.3
Bob = 76.8

upload_2016-2-12_10-9-14.png



Some of you have crazy cadence 140+ rpm

I think 140 would most likely be the Bkool Pro cadence estimate doubling up.

Geoff
 

LBHIFI

Veteran
Location
Liseleje
The fast starters are exploiting a weakness in the bkool simulation and the way that the trainers apply resistance.

When the trainer is not spinning it has no resistance (as the resistance depends on the metal disc moving under the magnets) and so if you hit it really hard from no/low rpm you can get a huge spike in speed before the resistance catches up.

I checked the max speeds for a few riders, and found the fast starters were hitting crazy speeds in the first 500 meters, particularly Bridgy, Bill and Rick!

BillS = 94.4 kph
LBHIFI = 70.8
Bridgy = 114.1
RickB = 86.3
Bob = 76.8

View attachment 118753




I think 140 would most likely be the Bkool Pro cadence estimate doubling up.

Geoff
Yes, unfortunately I cannot go faster than 70 kph. If I do my speed and power will be halved....and yet I just can't control myself. Every single Chain gang race I fall into this pit :banghead:.
 

gbrown

Geoff on Bkool
Location
South Somerset
BTW, it appeared that bkool's simulator is doing an adjusted speed for kickrs when going downhill. I've got no feel for its accuracy (still meaning to put in a reverse climb in bkool, ride it and compare to my real world data -- it's just not high priority right now).

I checked out recordings for the speeds of a number of the riders at 4.6 miles in at the end of the -4.6% decline just as it leveled out to -0.8% and got the following ..

Bridgy = 33.3 MPH @ 216 W
AlanC = 34.9 MPH @ 146 W
BillS = 34.9 MPH @ 178 W
Runar = 35 MPH @ 225 W
Roleur1 = 36.8 MPH @ 280 W
RickB = 40.7 MPH @ 170 W
Berty Basset = 32.6 MPH @ 161 W
John18 = 34.3 MPH @ 116 W
Alfie = 33.3 MPH @ 190 W
Steven = 33.6 MPH @ 152 W
Baldo = 34.1 MPH @ 148 W

Fairly consistent, but for some reason @RickB got about 20% faster. It looks like you go for it for a while (247 W) and then coast when up to speed. For whatever reason, @RickB gets about 20% more speed the entire descent than, say @bridgy!

@Roleur1, @Norseman and @bridgy, are you still going for it on the descents to get such power figures?

Apologies if I am giving away anyone's secret techniques!

Geoff
 

bridgy

Legendary Member
Location
Cheddar
I checked out recordings for the speeds of a number of the riders at 4.6 miles in at the end of the -4.6% decline just as it leveled out to -0.8% and got the following ..

Bridgy = 33.3 MPH @ 216 W
AlanC = 34.9 MPH @ 146 W
BillS = 34.9 MPH @ 178 W
Runar = 35 MPH @ 225 W
Roleur1 = 36.8 MPH @ 280 W
RickB = 40.7 MPH @ 170 W
Berty Basset = 32.6 MPH @ 161 W
John18 = 34.3 MPH @ 116 W
Alfie = 33.3 MPH @ 190 W
Steven = 33.6 MPH @ 152 W
Baldo = 34.1 MPH @ 148 W

Fairly consistent, but for some reason @RickB got about 20% faster. It looks like you go for it for a while (247 W) and then coast when up to speed. For whatever reason, @RickB gets about 20% more speed the entire descent than, say @bridgy!

@Roleur1, @Norseman and @bridgy, are you still going for it on the descents to get such power figures?

Apologies if I am giving away anyone's secret techniques!

Geoff

Re: your earlier post on the start speeds - I thought I got a good start! Sometimes I do the same but still get left behind at the start but it worked well for me this time for some reason!

On the downhills, I do back off if the descent is steep enough and the speed goes blue. I wonder if Rick for example was going faster at the top of the climb so carried more speed down it to explain the difference?

I guess that speed benefit when starting from low resistance is what some people exploit by the on/off power technique? I think it's a shame the software works like this because it's giving a benefit on the simulator for a technique that would actually be detrimental in real life, and I think they should try to make it as realistic as possible. I don't want to ride like that for the very reason that it's not realistic, but each to their own!
 

gbrown

Geoff on Bkool
Location
South Somerset
I guess that speed benefit when starting from low resistance is what some people exploit by the on/off power technique? I think it's a shame the software works like this because it's giving a benefit on the simulator for a technique that would actually be detrimental in real life, and I think they should try to make it as realistic as possible. I don't want to ride like that for the very reason that it's not realistic, but each to their own!

It could be a quite difficult to get around in the software, if it is an inherent weakness in the magnetic brake technology.

It is frustrating that if you don't do it, you can rarely catch anyone who does, so in effect you are forced to do it if you want to compete.

As you say, in real life no-one would get much of a benefit from starting so far above their threshold, they would be in oxygen debt right from the start, and it would take too long to regain the anaerobic capacity they had expended.

At the finish is a different matter, of course. I guess we all push a little too hard if it is close at the finish! :sweat:xx(

Geoff
 

bridgy

Legendary Member
Location
Cheddar
It could be a quite difficult to get around in the software, if it is an inherent weakness in the magnetic brake technology.

It is frustrating that if you don't do it, you can rarely catch anyone who does, so in effect you are forced to do it if you want to compete.

As you say, in real life no-one would get much of a benefit from starting so far above their threshold, they would be in oxygen debt right from the start, and it would take too long to regain the anaerobic capacity they had expended.

At the finish is a different matter, of course. I guess we all push a little too hard if it is close at the finish! :sweat:xx(

Geoff

I think someone said recently that this affect wasn't apparent in zwift due to the way it applied speed as you accelerate?
 

bobinski

Legendary Member
Location
Tulse Hill
The fast starters are exploiting a weakness in the bkool simulation and the way that the trainers apply resistance.

When the trainer is not spinning it has no resistance (as the resistance depends on the metal disc moving under the magnets) and so if you hit it really hard from no/low rpm you can get a huge spike in speed before the resistance catches up.

I checked the max speeds for a few riders, and found the fast starters were hitting crazy speeds in the first 500 meters, particularly Bridgy, Bill and Rick!

BillS = 94.4 kph
LBHIFI = 70.8
Bridgy = 114.1
RickB = 86.3
Bob = 76.8

View attachment 118753

Geoff

Fascinating Geoff,
My technique is to properly warm up, in the last minute or so spinning furiously at 100+ and then come to a standstill having changed up gears. I know i will hardly be able to turn the gear at the start but as soon as the timer hits go i begin to apply power and then push through. I know others will get away faster but i can sometimes keep the power up a little longer than some. Here i think we were hitting a slight incline too so that would have had an impact. Personally disappointing to think i am getting an unfair boost in some way. And while the real world observation is of course correct, deep down we know this is all a bit of a game!
 

LBHIFI

Veteran
Location
Liseleje
I guess that speed benefit when starting from low resistance is what some people exploit by the on/off power technique? I think it's a shame the software works like this because it's giving a benefit on the simulator for a technique that would actually be detrimental in real life, and I think they should try to make it as realistic as possible. I don't want to ride like that for the very reason that it's not realistic, but each to their own!
It's still a phenomenal workout though. Like doing intervals. I have come to the conclusion that there's no point in trying to avoid it: "did I exploit it there?", "was i slingshotting here?". There would always be some doubt, e.g. when you try to catch someone and ease off after catching, did you exploit the on/off technique?

Bkool knows about this glitch, and will hopefully have a fix ready in the near future.
 
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LBHIFI

Veteran
Location
Liseleje
I think someone said recently that this affect wasn't apparent in zwift due to the way it applied speed as you accelerate?
Yes, that was me. If I sprinted like in a Chan gang race, the feel would be the same, but the speed would start off blue and slowly rise as the brake resistance set in.
 

bridgy

Legendary Member
Location
Cheddar
It's still a fenomenal workout though. Like doing intervals. I have come to the conclusion that it there's no point in trying to avoid it: "did I exploit it there?", "was i slingshotting here?". There would always be some doubt, e.g. when you try to catch someone and ease off after catching, did you exploit the on/off technique?

Bkool knows about this glitch, and will hopefully have a fix ready in the near future.

You're right LB I do notice it when catching someone and then easing off when trying to get into position to draft. I wouldn't call it " exploiting" the technique though - it's more of an annoyance because I think it's one of the reasons getting settled in to draft someone is so hard!
 

RickB

professional procrastinator
Location
Norn Iron
I checked out recordings for the speeds of a number of the riders at 4.6 miles in at the end of the -4.6% decline just as it leveled out to -0.8% and got the following ..

Bridgy = 33.3 MPH @ 216 W
AlanC = 34.9 MPH @ 146 W
BillS = 34.9 MPH @ 178 W
Runar = 35 MPH @ 225 W
Roleur1 = 36.8 MPH @ 280 W
RickB = 40.7 MPH @ 170 W
Berty Basset = 32.6 MPH @ 161 W
John18 = 34.3 MPH @ 116 W
Alfie = 33.3 MPH @ 190 W
Steven = 33.6 MPH @ 152 W
Baldo = 34.1 MPH @ 148 W

Fairly consistent, but for some reason @RickB got about 20% faster. It looks like you go for it for a while (247 W) and then coast when up to speed. For whatever reason, @RickB gets about 20% more speed the entire descent than, say @bridgy!

@Roleur1, @Norseman and @bridgy, are you still going for it on the descents to get such power figures?

Apologies if I am giving away anyone's secret techniques!

Geoff
Very interesting to see actually as I never feel I catch anyone on the downhills. Quite a few occasions on long downhills where I've been within sight of lighter riders but never gain on them.

I've no secret technique - all try to do is make sure I've got the cadence back up before I come to the end of a hill so that I can maintain the speed on the flats as long as possible. At the point Geoff has taken a snapshot I'm at 170 watts I reckon I must be spinning nicely, but certainly not pushing hard at all. Doesn't explain why I'm faster than Roleur whos doing 280 watts!! I'm 84kg for reference.


On the downhills, I do back off if the descent is steep enough and the speed goes blue. I wonder if Rick for example was going faster at the top of the climb so carried more speed down it to explain the difference?
I never feel like I'm quick over the top of climbs and usually start 'freewheeling' a bit early as I see the speed drop then turn blue and pick-up. :unsure: I think Bill in the past has related a quick start downhill as being a factor for getting a higher freewheeling speed.


.I guess that speed benefit when starting from low resistance is what some people exploit by the on/off power technique? I think it's a shame the software works like this because it's giving a benefit on the simulator for a technique that would actually be detrimental in real life, and I think they should try to make it as realistic as possible. I don't want to ride like that for the very reason that it's not realistic, but each to their own!
Hear hear!! :cheers: I pedal pretty closely to how I would on the road and wont be changing (the one exception being the manic start off the line!! :laugh:)
 
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